4. Bring water to a boil, then whisk in chickpea flour mixture and reduce heat to medium-high. Continue to whisk for 3 to 4 minutes, until mixture thickens considerably. Whisk in oil and remove from heat. Pour into prepared loaf pan and use a rubber spatula to spread evenly. Refrigerate at least 2 to 3 hours or overnight.

5. When mixture has chilled and hardened, remove from refrigerator. Use the parchment paper to lift the block out of the pan. Slice block widthwise into 6 fillets.

6. Pour non-dairy milk into one shallow bowl, arrowroot powder into another, and breadcrumbs into another. Using one hand for wet ingredients and one hand for dry, dredge one chickpea fillet in milk and then in the arrowroot powder. Tap off excess arrowroot powder, then dredge in milk again, and finally in breadcrumbs. When fully coated, set on a plate and repeat with remaining fillets.

7. Line a plate with paper towels. Heat a large frying pan, preferably cast iron, over medium heat for 3 to 4 minutes. Liberally spray the bottom of the pan with olive oil and heat for 2 to 3 minutes. Place the fillets in the pan and cook for 3 to 4 minutes on each side, until crisp and golden brown all over. Transfer the fillets to paper towels.

8. Respray the pan with olive oil, add 1 tortilla, and cook for 30 seconds on each side, until heated but still soft and pliable. Remove from pan, place on a plate, and cover with a clean kitchen towel. Repeat with remaining tortillas.

9. To assemble the tacos, sprinkle a couple pinches of shredded cabbage and radish slices (if using) into the middle of a heated tortilla. Top with a chickpea fillet and the mango salsa. Serve with vegan tartar sauce, if using.